In
a mixer, beat the eggs. Add the 1/2 c. sugar and beat until light and
fluffy. Beat in the butter. Stir in the lemon peel, lemon juice and
orange peel. Add the yeast mixture and mix well. Set aside.

In
another bowl, blend the salt, baking powder, xanthan gum, guar gum,
brown rice flour, tapioca starch, potato starch and almond flour until
well mixed. Add to the liquid ingredients and beat on high for 1 minute.

Spoon into the pan. Let rise until doubled in bulk, which should take about an hour.

Bake
at 375 degrees Fahrenheit for about 20 minutes – adjust time for
differently-sized pans. For the 8" pan, keep an eye on it after 15
minutes: it should be nicely browned (don't underbake).

Let
cool. Remove from pan and ice. Decorate with multi-coloured sprinkles.
Once the icing has set, slice like bread to eat. Store in a
tightly-sealed container at room temperature.

Beat
the butter until fluffy. Beat in the icing sugar and salt. Add most of
the milk (because you might not need it all). Beat in the vanilla. You
are looking for an icing that is easy to spread and slightly loose so it
will "set" over the cake.